Drying system



W. H. SOLEM DRYING SYSTEM Dec. 4, 16962 2 Sheets-Sheet' l Filed Feb. 19, 1960 .r'l s fla.

FIC-ll MMMM ATTORNEY W. H. SOLEM Dec. 4, 1962 DRYING SYSTEM 2 Sheets-Sheet 2 INVENTOR.

WENDELL H. SOLEM Filed Feb. 19, 1960 ATTORNEY nited States Patent Mid-5,423 DRYNG SYSTEM Wendeli H. Salem, r2.5@ Walnut St., Boulder, Colo. Filled Feb. i9, 1969, Ser. No. 9,370 lil Qlaims. (Cl. 34-86) This invention relates to a drying system, such as including a drier of the type employed in laundries or dry cleaning establishments. More particularly, this invention relates to the supply of and regulation of the ow of air from an exterior source to one or more driers in such a system.

ln the drying of laundry in drying tumblers, large volumes of air are heated, as by gas, steam or electricity, and then drawn into a revolving tumbler or dryer where contact is made with the articles to be dried. This heated air causes the moisture in the articles to evaporate and the moisture laden air is then exhausted outside of the building, to prevent an undue rise in humidity inside the building. Normal current practice is to draw air for heating from the building in which the drier is located. Because the air discharged is exhausted outside of the building, it can readily be seen that there lmust be a continuous ow of air into the building to replace the air used by the drier or unfortunate results may be produced, particularly during the winter months. For example, during the winter months, persons have been made quite ill by carbon monoxide fumes in laundries due to large amounts of air taken by the driers and fumes from a space heater filling the laundry. Thus, when gas heat is utilized for heating purposes, a number of windows may be left open or partly open, or the partial vacuum created by the driers will draw air down the vent pipe for the space heater, thus filling the building with gas fumes. However, having these windows partly open creates a heating problem, so that it is often quite diicult to keep the place comfortably Warm.

Research conducted by the American Institute of Laundering has revealed that, in laundries where dry-cleaning is also carried on, the fumes from the cleaning solvents are often drawn into the drying tumblers and cause a chemical reaction with the hot moisture laden air, which releases minute droplets of acid which damage some fabrics in the drier. Also, the relative humidity in most laundries is rather high and if this humid air is drawn into the driers, a rather long period of time will be lrequired to evaporate water from the material in the drier. Air in laundry rooms is also frequently laden with soap dust, bleach, fumes and other impurities which can impart an unpleasant odor to the drying clothes.

Among the objects of the present invention are to provide a novel drying system which includes one or more dryers to which air to be heated is supplied; to provide such a system having an increased eiliciency and effectiveness in drying; to provide such a system which increases the safety and santitation of drying; to provide such a system in which an effective control of the flow of air from an exterior source to an enclosed dryer installation is maintained; to provide such a system in which the exhaust air from the dryer or dryers may -be employed in heating the incoming supply of air; and to provide such a system which is readily installed and is effective in operation.

Additional objects of the present invention and the novel features thereof will become apparent from the following description, taken in connection with the accompanying drawings, in which: A

FlG. 1 is a front elevation, partly in vertical section and partly in diagrammatic, of a dryingV system constructed in accordance with the present invention;

FIG. 2 is a partial vertical section, taken online 2--2 of FlG. 1;

dddg Fatentecl Elec. 4, i962 FIG. 3 is a front elevation, on an enlarged scale, of a preferred form of device for controlling the introduction of fresh air into the drying system of FIG. 1; and

FIG. 4 is a vertical section taken on line 4 4 of FIG. 3.

Referring more particularly to the drawings, there is illustrated in FIGS. 1 and 2 a drying system of this invention installed in a building having a lower enclosed space or room L provided by walls ld and ll, a floor 12 and a ceiling or roof 13. One or more dryers D are mounted in convenient relation, such as side by side, within the lower room L, one wall of which may abut the front of each dryer, with access to the dryers for placing articles to be dried in the dryers and removing the same therefrom after drying provided by an access opening 14 of FIG. 2. A suitable insulating and sealing material, such as asbestos, may be placed between wall ll and the front of each dryer D. It will be noted that, in the systern shown, the space in which dryers D are installed is totally enclosed, except for an opening l5 leading to an upper enclosed space U, although the opening 15 may be connected with the air intakes 16 of the dryers by suitable conduits. The upper space or room U is formed by walls 17 and a roof 18, with at least two of the walls 17 being outside walls and the roof 13 of lower room L forming a oor for space U, in the penthouse arrangement shown. One or more heat exchangers H, corresponding to the number of dryers D, are installed in the upper space U, Within an enclosure E having end walls 19, side walls 20 and a top 21, while an air control device C is installed at several suitable positions around enclosure E, such as opposite the heat exchangers H in end walls 19 and also in the top 21. The preferred constructions of the heat exchangers H and air control devices C are described later.

The dryers D are representative of various conventional forms of dryers, such as those employed in laundry installations, and commonly referred to as drying tumblers, and where, in accordance with well known practice, large volumes of air may be heated by means such as gas, steam electricity and the like, for introduction into the tumblers, where contact is made with the articles or material to be dried. For example, each of the dryers D may include a housing 22 within which is mounted a revolving tumbler' 23, which is generally a hollow perforated cylinder, the housing being provided with a front access door 24 for the insertion and removal of articles, such as laundry or dry cleaning. A heating unit is mounted within an inlet hood 25, the open sides of which form air intakes 16, while a drive motor 26 is disposed at the lower rear end of the housing for driving an exhaust fan 27, located at the mouth of an exhaust duct 28, and also for driving a shaft for rotation of the tumbler 23 through gearing 29 and other suitable means, not shown. Each dryer D may also be provided with suitable controls, such as a temperature indicator and a thermostat responsive to the temperature of the outgoing air, as well as suitable switches and dials, for controlling the operation of the dryer, all of which are not shown since they are well known accessories provided on dryers. The more usual temperatures to which the incoming air is heated are between F. and 190 F., depending upon the type of fabric to be dried, and lthe dryer controls may be set so that the dryer will be automatically shut olf when the exhaust air approaches the temperature of the incoming air. The dryer may also be controlled by a timer, which may `be set for operation of the dryer for a predetermined amount of time. In general, the temperature and time settings for the dryer are governed by the size of the tumbler and load and the environmental conditions in the building, such that air Will be introduced into the tumbler at a selected temperature and in controlled amounts to most effectively establish drying of the material therein.

The air heated by the heating unit in each inlet hood 25 passes downwardly through the drum 23, through the suction produced by fan 27, as indicated by arrows Ztl, then upwardly through an exhaust duct 2S, as indicated by arrows 31, to enter the heat exchanger H at an upper position in the rear end thereof. Ducts 2S conveniently extend upwardly through roof or ceiling 13, rearwardly of opening. 15, as in FlG. 2.. Each heat exchanger H is conveniently rectangular and provided with thin metal walls for maximum heat transfer through the walls. After passage through the heat exchanger, the exhaust air, which is indicated by arrows 32 and which has been cooled through heat exchange with incoming fresh air, is discharged to the atmosphere through a stack 33 which is connected at its lower end to the front of the respective heat exchanger H, at a lower position thereof, and extends upwardly through the roof 1S of the upper enclosed space U. Fresh air from the atmosphere, indicated by arrows 34, enters through openings 35i in wall 17 of the upper room U, each opening 35 being provided with a iilter 36 to remove soot or other substances which might be undesirable for contact with the material or articles in dryers D. The incoming fresh air flows around the enclosure E and enters the enclosure through the air control devices C for flow around the outside of the heat exchangers H, as indicated by arrows 37, thereby recovering from the exhaust air a portion of the heat utilized in drying the material or articles in the dryer. The preheated incoming fresh air, indicated by arrows 38, then passes downwardly through opening 15 and thence to air intakes 16 of the dryers.

In accordance with the present invention, each of the air control devices C is especially constructed so as to be responsive to the difference in pressure between the inside and outside of the enclosure E, so that only the amount of air necessary to supply the demands of fans 27 will enter enclosure E. This is an important feature of the present invention, since the amount of incoming air necessary for drying will depend not only upon the. temperature of the outside air, but also its humidity. That is, the ability of the heated air to extract moisture from the articles or material to be dried is dependent not only upon the temperature to which the air is heated, but also the residual moisture which it contains. The ability of one pound of dry air to extract moisture is limited to the number of 'grains of moisture which one pound of dry air, at any given temperature, will contain when saturated with moisture, i.e., reaches its dew point. Thus, during the sum- 'mer months when the outside temperature is normally much higher, but the relative humidity may be lower, the total volume of air necessary to be circulated through the dryer may be greater than during the winter months, when the outside air temperature is normally much lower, although the relative humidity may be higher. For instance, if the temperature of the outside air is at or below freezing, each cubic foot of air can be heated to a lower temperature, to extract the same amount of moisture from the articles or material to be dried, since the number of grains of moisture per pound of dry air in the outside air is small. However, if the relative humidity is high, even though the temperature of the outside air is higher, such as 80 or 90 F., a larger total volume of air will be required for drying, or the air might be heated to a higher temperature, since each cubic foot of air already contains a greater percentage of moisture. One of the advantages of the air control devices C is that if a lesser volume of air is required, such as during the winter months, only that volume will be admitted to the enclosure E and the smaller volume of air thus will be heated to a higher temperature by the heat exchanger H, thus increasing the .efficiency of the operation. However, when a larger volume of air is required, the air control devices C will permit the same to enter the enclosure E, thus assuring operations under the desired conditions. A further advantage of the air control devices `C is that, when the dryers are not in operation and therefore no air is being pulled through the dryers, the air control devices will close, thereby preventing reverse circulation of air to the atmosphere and not only retaining partially heated air in enclosure E, but also trapping heat produced by radiation and convection from the dryers themselves.

A suitable air control device C is shown in FIGS, 3 and 4, although it will be understood that other devices operating on a similar principle or even fans turned by a variable speed motor, in turn controlled by the requirements of the dryers, may be used. Each air control device C comprises a hollow, tubular conduit 40 in which is installed a butterfly plate 41 attached to one flange of a pivot angle 42, each end of which is received in a collar 43 mounted on a frange 44 of a. closure plate 45. When the air control device C is installed in the side of enclosure E, plate 41 will be upright with the parallel sides thereof upright and the top and bottom being curved to correspond to the inside of conduit 4t), while the inner edges of plates 45 and flanges 44 thereof will be upright and the outer sides of plates 4S will be arcuate to correspond to the inside of conduit 40. To cause plate 4l to swing open, as to the dotted position of FIG. 4, in accordance with the suction in enclosure. E, produced by the withdrawal of air from within the enclosure by the blowers 27, a weight 46 is adjustably mounted, as by threads, on a pin 47, the inner end of which is attached, as by welding, to plate 41 adjacent the lower edge thereof and at least below the angle 42. Thus, when suction is produced in enclosure E, the plate 41 will swing inwardly until the effect of weight 46, the center of gravity of which will move outwardly as plate 41 swings inwardly about angle 42 as an axis, will equal the force on the inner side of plate 41 due to suction. Thus, plate 41 will swing to a balanced position, depending upon the suction in enclosure E, i.e., the pressure differential between the inside of enclosure E and the outside thereof. As will be evident, the suction in enclosure E will be directly related to the demand for air of the dryers D, so that the amount of fresh air permitted to enter enclosure E will correspond to the demand therefor by the dryers. Also, if the demand should increase or decrease, plate 41 will swing further inwardly or swing outwardly, back toward the inlet end of conduit 40, respectively. Preferably, the angle 42 or pivot for plate 41 is disposed below the center of the plate, so that plate 41 will swing inwardly more readily.

Conduit 40 may be formed of light sheet metal, as may also closure plates 45, while butterfly plate 41 may be slightly greater in thickness to support weight 46. Each collar 43 is conveniently attached to ange 44 on the side opposite plate 41, surrounding a hole in flange 44, although collar 43 is shown in full in FIG. 4 for clarity of illustration. Collars 43 may be attached to flanges 44 by brazing, or in any other suitable manner, while plate 41 is conveniently riveted to one flange of angle 42 and closure plates 45 are each conveniently provided with a flange 48 around the outside for attachment, as by riveting, to conduit 40.

As indicated above, when air control device C of FIGS. 3 and 4 is installed in one end of enclosure E, plate 41 will be upright in closed position. However, when air control device C is installed in the top of enclosure E, butterfly plate 41' will be horizontal or substantially horizontal when in closed position and will swing downwardly to open. For this installation, angle 42 is preferably shifted to the center of plate 41' and a pin 47' with a weight 46' is preferably attached to angle 42' on the underside thereof, so as to hang directly downwardly when plate 41' is closed and to swing outwardly from the center as plate 41 opens, as shown in FIG. 1, so that weight 46 will provide an increasing resistance to further opening movement of plate 41' as plate 41 swings further open. Thus, plate 41 will open to a position corresponding to the pressure differential between the inside and outside of enclosure E, thereby permitting a flow of fresh air into the enclosure E corresponding to the demand by the dryers D.

From the foregoing, it will be evident that the drying system of this invention fulfills to a marked degree the requirements and objects hereinbefore set forth. By supplying outside air to the dryers, and by using a circuit for the air supplied to and exhausted from the driers which is separate from a laundry or other establishment in which the dryers are used, the possibility of the withdrawal of air from a room or enclosure is prevented, so that a gas heater or the like will not be unduly affected. By heat exchange of exhaust air from the dryers with incoming air, the eiciency and effectiveness of the dryers is improved. Particularly by controlling the flow of outside air to the heat exchangers in accordance with the demand for air created by the dryers, the effectiveness land efficiency of the dryers is further improved. As will be evident, the air control devices C are particularly useful, being responsive to the differential in pressure between an enclosure in which the heat exchangers are located and the exterior of such enclosure, although, as indicated previously, other air control devices may be used.

Although a preferred embodiment of this invention has been illustrated and described, it Will be understood that other embodiments may exist and various changes may be made in addition to those indicated, without departing from the spirit and scope of this invention.

What is claimed is:

l. In a drying system within a building, including at least one dryer having means for heating air and causing such heated air to contact articles in said dryer, and means for discharging air therefrom after contact with such articles, comprising an enclosure within said building; means for supplying atmospheric air to said enclosure; heat exchange means in said enclosure; means for supplying air discharged from said dryer to said heat exchange means; means for exhausting to the atmosphere the air supplied from said dryer after passage through said heat exchange means; means for supplying air from said enclosure to said dryer after heating thereof by said heat exchange means; and means responsive to the flow of air through said dryer for controlling the flow of air into said enclosure.

2. In a drying system as set forth in claim 1, including a plurality of dryers; and a corresponding number of heat exchangers in said enclosure and each connected to the discharge of one of said dryers.

3. In a drying system as set forth in claim 1, wherein said enclosure is provided with an opening; and wherein said means for controlling the flow of atmospheric air into said enclosure comprises a movable plate pivoted in said opening; and a weight attached to said plate for urging said plate to close said opening.

4. In a drying system, as set forth in claim 3, wherein said opening is circular and in an upright wall of said enclosure; and including a tubular conduit in said opening; an upright, stationary plate attached to and at each side of said conduit, each said upright plate having an outer edge conforming in shape to said conduit, an upright inner edge and a ilange extending inwardly of said conduit from said inner edge; a bearing collar attached to each said ange below the center of said conduit; an angular pivot for said movable plate having its opposite ends in said collars, said movable plate being attached to said pivot and having a shape corresponding to the area between the inner edges of s aid stationary plates and the upper and lower portions of the inside of said conduit between said stationary plates; and a pin extending downwardly from the lower portion of -said movable plate, said weight being adjustably mounted on said pin.

5. In a drying system as set forth in claim 3, wherein said enclosure is provided with a top having an opening and said movable plate corresponds in shape to and is disposed in said opening; and including a pivot for said movable plate attached centrally thereto and extending in horizontal position across said opening; and a pin extending downwardly from said pivot, said weight being adjustably mounted on said pin.

6. In a drying system as set forth in claim `1, wherein said enclosure has upright walls and a top, with an opening in said top and in at least one wall; and said means for controlling the iiow of air into said enclosure is disposed in said openings.

7. In a drying system, including a plurality of dryers, each having an air inlet, means for heating air and causing such heated air to contact articles in said dryer, and means for discharging air therefrom after contact with such articles, comprising a lower room in which said plurality of dryers are disposed; an upper room having upright walls, at least two of which are open to the atmosphere and provided with openings for admitting atmospheric air into said upper room; an enclosure disposed in said upper room and having upright walls and a top spaced from the corresponding portions of said upper room, each upright wall of said enclosure opposite a wall of said upper room exposed to the atmosphere having an opening therein and the top of -said enclosure also having an opening; a plurality of heat exchangers, corresponding in number to said dryers, disposed in said enclosure; a duct connecting the discharge of each dryer with one of said heat exchangers; a duct extending from each heat exchanger through said enclosure and then through said upper room and to the atmosphere, for discharging the air supplied to said heat exchanger by the corresponding dryer; means for supplying air from said enclosure to the inlets of said dryers; and means disposed in each opening of said enclosure for controlling the flow of air into said enclosure in accordance with the iiow of air from said enclosure.

8. In a drying system as set forth in claim 7, wherein said upper room is directly above said lower room and the ceiling of said lower room forms a floor for said upper room; and said means for supplying air f'rom said enclosure to said dryer inlets includes an opening in said ceiling of said lower room and communicating with the in1 terior of said enclosure.

9. In a drying system as set forth in claim 7, including an air filter disposed in each opening in said upper room walls.

10. In a drying system as set forth in claim 7, wherein each said means controlling the flow of air into said enclosure comprises a movable plate pivoted in an enclosure opening; and a weight attached to said plate and urging said plate toward a position closing said opening.

References Cited in the tile of this patent UNITED STATES PATENTS 1,418,386 Maus June 6, 1922 1,792,137 Bethke Feb. 10, 1931 2,284,165 Porwancher May 26, 1942 2,388,253 Dady Nov. 6, 1945 

